[SYCL] Disable HostPtr reuse when the pointer is read-only

[0x12CC]

Mutable SYCL buffers can be initialized using a const T* hostData. This change ensures that these buffers allocate new memory so that their contents can be modified without changing the original host data. Fixes #10091.

[steffenlarsen]

Great find! 🚀

[bader]

@0x12CC, @steffenlarsen, @againull, in my pre-commit the test fails on CUDA and Intel:

FAIL: SYCL :: Basic/host_write_back.cpp ([19](https://github.com/intel/llvm/actions/runs/5546033087/jobs/10129281860?pr=10363#step:16:20)0 of 1436)
******************** TEST 'SYCL :: Basic/host_write_back.cpp' FAILED ********************
Script:
--
: 'RUN: at line 1';    /__w/llvm/llvm/toolchain/bin//clang++   -fsycl -fsycl-targets=nvptx64-nvidia-cuda /__w/llvm/llvm/llvm/sycl/test-e2e/Basic/host_write_back.cpp -o /__w/llvm/llvm/build-e2e/Basic/Output/host_write_back.cpp.tmp.out
: 'RUN: at line 2';   env SYCL_PI_CUDA_ENABLE_IMAGE_SUPPORT=1 ONEAPI_DEVICE_SELECTOR=ext_oneapi_cuda:gpu  /__w/llvm/llvm/build-e2e/Basic/Output/host_write_back.cpp.tmp.out
--
Exit Code: -6

Command Output (stdout):
--
$ ":" "RUN: at line 1"
note: command had no output on stdout or stderr
$ "/__w/llvm/llvm/toolchain/bin//clang++" "-fsycl" "-fsycl-targets=nvptx64-nvidia-cuda" "/__w/llvm/llvm/llvm/sycl/test-e2e/Basic/host_write_back.cpp" "-o" "/__w/llvm/llvm/build-e2e/Basic/Output/host_write_back.cpp.tmp.out"
# command stderr:
clang++: warning: CUDA version 12.1 is only partially supported [-Wunknown-cuda-version]

$ ":" "RUN: at line 2"
note: command had no output on stdout or stderr
$ "env" "SYCL_PI_CUDA_ENABLE_IMAGE_SUPPORT=1" "ONEAPI_DEVICE_SELECTOR=ext_oneapi_cuda:gpu" "/__w/llvm/llvm/build-e2e/Basic/Output/host_write_back.cpp.tmp.out"
# command stderr:
host_write_back.cpp.tmp.out: /__w/llvm/llvm/llvm/sycl/test-e2e/Basic/host_write_back.cpp:[31](https://github.com/intel/llvm/actions/runs/5546033087/jobs/10129281860?pr=10363#step:16:32): void testHostAcessor(): Assertion `vec[0] == 1' failed.

error: command failed with exit status: -6

--

********************

Any ideas why?
https://github.com/intel/llvm/actions/runs/5546033087/jobs/10129281860?pr=10363 - CUDA log.
https://github.com/intel/llvm/actions/runs/5546033087/jobs/10129281286?pr=10363 - Intel log.

[bader]

@aelovikov-intel told me that it's caused by misalignment between the compiler and tests, which is supposed to be fixed by 7c8932a. I.e. this is CI scripts issue.